In order to maintain a high level of efficiency at a worksite it is often desirable to operate an off-highway vehicle at the vehicle's maximum safe speed. The maximum safe speed at which an off-highway vehicle can be operated is dependent on many variables including, but not limited to, load and road conditions. To maintain the off-highway vehicle at or near the maximum safe speed an operator must continuously control the throttle and brake via conventional foot operated pedals. Operators of off-highway vehicles often work long shifts, and continuous throttle and brake control throughout the course of the shift can lead to undesirable driver fatigue.
Currently, an off-highway vehicle may be equipped with a conventional cruise control system that may be used to maintain a speed set by the operator. However, under certain conditions, this set speed may not be achievable. For example, when a fully loaded off-highway vehicle ascends a 25% gradient hill, the vehicle nay be unable to attain 20% of its rated maximum speed. As a further example, when a fully loaded off-highway vehicle descends a 25% gradient hill, setting the vehicle speed at 50% of the maximum rated speed may create a situation where the brakes will be unable to maintain the set speed.
Additionally, there exists a conventional retard lever which may be manipulated by the hands of an operator. However, the conventional retard lever only provides vehicle descent speed control. Therefore, an operator must still manipulate the conventional foot operated throttle when encountering a flat road or ascending a hill.